1. Field of the Invention
The present invention relates to a disposable dental prophylaxis apparatus for use in scaling, grinding, or polishing the surface of teeth in dental fields, and more particularly, to a disposable dental prophylaxis apparatus that is capable of discharging a predetermined amount of dentifrice material therefrom such that dentists can effectively perform their desired dental operations with the dentifrice material discharged therefrom.
2. Description of the Prior Art
Presently, there have been provided various kinds of disposable dental prophylaxis devices in the art. For the full comprehension of this invention, two prior art inventions among them are suggested in this description, first of which is disclosed in U.S. Pat. No. 4,266,933 entitled ‘ROTARY DENTAL POLISHING APPARATUS’ and filed on May 12, 1981 (hereinafter, referred to as “first prior art”), and second of which is disclosed in U.S. Pat. No. 6,257,886 entitled ‘DISPOSABLE DENTAL PROPHYLAXIS ANGLE’ and filed on Jul. 10, 2001 (hereinafter, referred to as “second prior art”).
Referring first to the first prior art, the rotary dental polishing apparatus includes a hand piece adapted for controlling rotating operations, a housing adapter, and a cartridge for housing polishing paste therein.
In the first prior art, the cartridge may be in a linear or perpendicular shape with respect to the hand piece, and it has a ribbon type of screw conveyor mounted at the inside thereof and a polishing cup coupled at one side end portion thereof.
The cartridge and the polishing cup have respective holes formed in the middle portions thereof in such a manner as to communicate with each other, such that the polishing paste at the inside of the cartridge can flow into the polishing cup.
On the other hand, while the housing adapter or a cylinder housing coupled to the hand piece is being rotated by means of the mechanism of gears connected thereto, at the state where the ribbon type of screw conveyor mounted at the inside of the cartridge stops without rotating, the polishing paste charged at the inside of the cartridge is supplied to the polishing cup through the hole formed in the middle portion thereof.
Unfortunately, the first prior art is well explained with the help of the drawings and description, but actually, it fails to satisfy some practical conditions such as the structural conditions in a manufacturing process, the cost conditions in a distributing process, and the physical operation principles in practical uses, such that the product is not really made or used at all in this related art up to now after this patent has been granted. The reason why the first prior art is not available can be apparently appreciated from the structural characteristics the presently popular disposable dental prophylaxis apparatus have had.
Referring now to the disposable dental prophylaxis apparatus presently popular in the art, the adapter that is adapted for being inserted into a hand motor has the whole length of about 46 mm. Next, referring to the thickness of the adapter, that is, to the diameter of the tube, the thick portion has a diameter of about 11 mm and the thin portion has a diameter of about 8.4 mm, such that it is appreciated from the sizes of the adapter that it is a very tiny part. More particularly, the head portion of the adapter that is inserted deeply up to the back tooth of a patient's mouth has a diameter of about 8.4 mm and a height of about 10.5 mm.
Specifically, if the thickness of the adapter tube of about 2 mm is subtracted from the whole diameter thereof, the inner diameter of the head portion is just 6.4 mm. By the way, according to the first prior art, the ribbon type of conveyor is housed in the tiny space of the cartridge and further, the polishing paste is charged at the inside of the cartridge, which fails to sufficiently consider the supply and demand laws that should be satisfied from the manufacturing process to the practical use process.
In addition to the structural difficulties the first prior art has as mentioned above, it has the operational difficulties wherein the screw conveyor stops while the cartridge is being rotated, thereby discharging the polishing paste therefrom. Physically, this is like the principle where an automobile starts at the state of being braked, and in this case, as a substantially strong force is applied to the inside of the cartridge, the conveyor becomes twisted, which makes it impossible to discharge the polishing paste therefrom. Furthermore, the rotating force is not transferred well by the application of the substantially strong force, which causes power braking such that the gears adapted to be in engagement with each other are abrasive to run idle.
For these reasons, it is found that the patent right of the first prior art is terminated, while not put into practical use.
Referring next to the second prior art, it can be appreciated that the second prior art is a much more improved invention than the first prior art.
Apparently, the second prior art is more excellent than the first prior art. The first prior art employs the rotary cartridge having the ribbon type conveyor mounted therein, and contrarily, the second prior art employs a structure wherein a dentifrice material is charged into a housing and is then discharged by the pushing force of a piston.
According to a first aspect of the second prior art, if an actuator surrounding a drive shaft is pushed to move a flange forwardly, a dentifrice material that is charged in a housing flows to an upper channel portion and is supplied to a prophylaxis cup through a delivery channel portion. According to a second aspect of the second prior art, if a cam is pressed to forwardly move a push rod having an inclined face formed at one side end in such a manner as to surround the drive shaft, a spring is compressed to make a dam push the actuator such that the dentifrice material is discharged to the prophylaxis cup through the upper channel portion. According to a third aspect of the second prior art, a plate-like primary drive gear is mounted at the end portion of the drive shaft, having a through hole adapted for discharging the dentifrice material therefrom, such that the dentifrice material can be supplied to the prophylaxis cup.
However, according to the above-mentioned aspects of the second prior art, as the charged dentifrice material undesirably sticks to the shaft when the shaft is rotated, power braking severely occurs on a hand piece motor, which results in high heat generation on the hand piece motor.
In addition, as the shaft is rotated at the state of being buried into the dentifrice material, the rotating force of the shaft is not exerted well as if a boat is not advanced well by the application of high water pressure caused by the rotation of a screw under the water.
Thus, the prophylaxis cup that has to be rotated at a high speed is not really rotated rapidly, which loses its friction function against a patient's tooth. As the shaft and the dentifrice material rubbing against each other generate large heat at the inside of the shaft, the dentifrice material may be changed in its original quality.
Moreover, the second prior art is very complicated in its structure, which makes it hard to perform a mold-manufacturing process and an injection molding process, and specifically, even though all parts are made, they could not be assembled structurally with one another, such that no final product is made up to present.